Brucellosis issues in Wyoming
by Albert Sommers, House District #20 Representative
December 21, 2019
12-21-2019
Hello Sublette County, this is Albert Sommers reporting to you from Cheyenne on issues relating to brucellosis. The infectious bacterial disease brucellosis, in this case b. abortus, causes cattle to abort their calves. Brucellosis is a zoonotic disease that can affect other species, including humans. Because this is a zoonotic disease, it is regulated by both federal and state livestock health agencies. Brucellosis has been primarily eradicated from cattle herds in the United States, except in the Greater Yellowstone Area, where the disease is endemic in elk and occasionally jumps species to cattle. This fall, brucellosis issues have plagued Sublette County ranchers, including the Sommers Ranch.
Cattle producers in Sublette, Teton, Park, and northern Lincoln counties are in the Designated Surveillance Area (DSA). The State of Wyoming requires sexually intact female bovines to be tested for brucellosis prior to movement outside the DSA. In order to test for brucellosis, veterinarians take blood samples from cattle and send the samples to the Wyoming State Vet Lab (WSVL) in Laramie, where the samples are screened utilizing testing procedures approved by the federal government (USDA-APHIS). A WSVL white paper, created at my request, states "as brucellosis serologic testing began to increase last fall, it started to become apparent that the WSVL and other labs were seeing more suspect and positive samples... It is important to note that the numbers of ‘non-negative’ tests have not been enormous, 16 animals from 12 premises throughout DSA tested in the positive (>20) or suspect (10-20) range on FPA out of roughly 80,000 tested. For three of these animals, we are reasonably confident they are true infected animals." Those positive samples, regardless whether the herd is designated an "infected herd," create serious repercussions for cattle producers.
On our ranch, Sommers Ranch, a non-pregnant yearling heifer tested positive. This positive test forced the Wyoming State Veterinarian to put a movement quarantine on all the ranch’s sexually intact cattle, except those sent direct to slaughter sale. Nearly one month later, the federal epidemiologist released our herd, and the Wyoming State Vet released the quarantine. We were not alone, and the story does not end there. Every neighbor whose cattle had commingled or had fence line contact with my heifer was left with the decision of whether to test their cattle or wait to see whether my animal was infected. Most producers whose cattle had contact with ours tested their cattle for brucellosis. This resulted in thousands of cattle being tested, and subsequently more positives being found. A positive on the test does not necessarily equate to an infected animal; therein lies the rub. Although the number of animals with a positive test result was small, the number of affected premises was several times what is typically found during fall marketing.
Why?
According to WSVL, "For the past 20-plus years, the rapid automated presumptive test (RAP) has been the screening test for brucellosis in cattle in Wyoming. The diagnostic reagent required to run the RAP test was supplied solely by USDA-APHIS. Earlier this summer (2019), the WSVL and other labs were notified by APHIS that they would no longer be able to supply the RAP reagent, effectively eliminating RAP as an available test. Two other tests are available for serologic screening for brucellosis: the buffered acidified plate antigen (BAPA) and the fluorescence polarization assay (FPA), the test previously used to confirm RAP results… Thus, in consultation with the Wyoming State Veterinarian and diagnosticians in other states it was decided that we would utilize the FPA test for screening. The FPA test is a much more sensitive and specific test than either RAP or BAPA (both sensitivity and specificity >99%)." Producers were not notified that a testing change had occurred until the county’s producers were in the middle of testing thousands of cattle. Producers, brand inspectors, and veterinarians were kept in the dark.
At this same time, the Wyoming State Veterinarian was pulling out what was left of his hair, because he was required to track all these positive tests, and assume they were infected animals. Tracking such cases is not simple, and a lot of investigative work is required. Brucellosis hides in various organs, and really doesn’t manifest itself until late in pregnancy, meaning it is hard to find even through culture tests. I believe the State Vet did the best job he could under the circumstances and regulations he faced. More communication with all producers would have been beneficial, but confidentiality issues seemed to prevent that. Communication with producers, veterinarians, and brand inspectors must improve, regardless of how busy the animal health agencies are. So, what has been done by the regulators? What am I trying to do at the state level?
Regarding the FPA test, WSVL states: "Current solution: In consultation with and provisional approval by APHIS, the lower cutoff values for FPA testing have been raised from 20 to 40, provided other tests are negative. The BAPA has been implemented as a follow-on test. Under this scheme, if an animal has an FPA value <40 and is BAPA negative it will be considered negative. Sera that test >40 on FPA and/or are BAPA positive will be sent to the APHIS National Veterinary Services Laboratory for further testing. Using these criteria, five of the 16 FPA positive animals would have been called negative." Federal and State animal health regulators continue to evaluate current cases. It may not be possible to determine the true brucellosis status of certain animals due to the nature of the infection in cattle.
If this is the "current solution," what is the long-term solution? The FPA test appears to be too unreliable, so we need research for the development of a new diagnostic brucellosis test. Further, we need a new vaccine. Producers have little confidence in RB51, the present vaccine, so most producers would like to return to the old Strain 19 vaccine or see a new vaccine be developed. However, vaccine companies are not going to spend money in this arena, because there are not enough livestock in the DSA to warrant spending R&D dollars. The federal government needs to fund USDA-APHIS to ensure the RAP test is reinstated. Adequate federal dollars could also move the needle on vaccine research.
The workload upon the WSVL has been intense, and it has been working with a short staff for many years. That is where I can try to help. As we build the budget for the upcoming budget session, I will be trying to get more pathologist positions for the WSVL. In testimony in front of the Appropriations Committee, the UW College of Agriculture Dean testified that the WSVL was short four positions. As a member of the Appropriations Committee, I will work toward providing two additional positions, but not four. I heard that producers and veterinarians were receiving lab results as late as one in the morning. People don’t do their best work at 1 a.m. After being approached by one of the affected producers, I am drafting a bill that would provide some reimbursement to producers for costs incurred from future brucellosis quarantines. This could be done by accessing an existing pot of money dedicated to brucellosis. Wyoming’s wildlife now harbors this disease, so I believe the State has some responsibility to lessen the impact on ranchers. I am also examining the Wyoming Livestock Board budget to ensure it has enough money to reimburse the WSVL for brucellosis testing. Joel Bousman, Terry Pollard, and I have served on the Brucellosis Coordination Team since its inception in the mid-2000s. There are no easy answers. The solutions most talked about, like elimination of elk feedgrounds, test and slaughter of infected elk, spatial separation of elk and cattle, and a new vaccine, all have unique challenges, detractors, and proponents.
At the Pinedale Library on January 28 at 1 p.m., The Sublette County Conservation District is holding a meeting for livestock producers to discuss concerns about this past fall’s brucellosis testing. Participants will include the State Veterinarian, WSVL, USDA-APHIS, Wyoming Department of Agriculture, Wyoming Livestock Board, and the Wyoming Game and Fish Department.
I can be reached at albert@albertsommers.com.
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